NEW THIS THURSDAY: FIVE REVIEWS AND EVALUATIONS OF MALARIA RAPID DIAGNOSTIC TESTS/ ROUTINE PARALLEL DIAGNOSIS OF MALARIA USING MICROSCOPY AND THE MALARIA RAPID DIAGNOSTIC TEST

Tuesday, 30th of July 2013

FIVE REVIEWS AND EVALUATIONS OF MALARIA RAPID DIAGNOSTIC TESTS

The use of thick film microscopy for malaria diagnosis is attended by many drawbacks, notably the time lag between taking the sample in the bush dispensary and waiting for the results from the hospital lab, sometimes weeks later. The RDT, a point of use test, permits the peripheral facility, without microscopy, to do primary lab work on the spot and, with a positive result, undertake treatment immediately.

The interagency guidelines, at http://www.wpro.who.int/malaria/NR/rdonlyres/D4FA2361-9894-4ABE-9639-7D4CF798836B/0/METHODSMANUALMalRDTPT_FINAL_Version5.pdf (2012 edition) give technical advice for those introducing RDTs. Assessments of RDTs can be found at http://apps.who.int/iris/bitstream/10665/77748/1/9789241504720_eng.pdf

Good reading.

ROUTINE PARALLEL DIAGNOSIS OF MALARIA USING MICROSCOPY AND THE MALARIA RAPID DIAGNOSTIC TEST

Malar J. 2013 May 21;12(1):167.

Routine parallel diagnosis of malaria using microscopy and the malaria rapid diagnostic test: the experience of Medecins Sans Frontieres in Myanmar.

Kosack CS, Naing WT, Piriou E, Shanks L.

Abstract below; full text is at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663673/

BACKGROUND:

Malaria rapid diagnostic tests (RDTs) are commonly used in Medecins Sans Frontieres (MSF) programmes to detect acute malaria infection. Programmes in regions with both Plasmodium falciparum and non-falciparum malaria (i.e. Plasmodium ovale, Plasmodium malariae and Plasmodium vivax) use a three-band P. falciparum/Pan test such as the SD Bioline Malaria Ag P.f/Pan 05FK60 (Standard Diagnostics, Kyonggi, Republic of Korea), hereafter referred to as SD 05FK60, as used by the MSF-Holland clinics in Rakhine state, Myanmar. In spite of published reports of generally good test performance, medical and paramedical staff on the ground often doubt the diagnostic accuracy of these RDTs.

METHODS:

Parallel testing with malaria microscopy and RDT was conducted at two clinics in Rakhine state, Myanmar, for a period of 14 months as a programmatic response due to doubts and concerns of medical and paramedical staff into malaria RDTs.

RESULTS:

A total of 2,585 blood samples from non-pregnant suspected malaria patients were examined by the SD 05FK60 RDT and microscopy at two clinics in Myanmar from October 2010 to December 2011. The reference standard microscopy diagnosed 531 P. falciparum and 587 P. vivax or P. malariae mono-infections. The overall sensitivity for P. falciparum detection by the SD 05FK60 was 90.2% (95% CI: 87.4-92.6) and for P. vivax/P. malariae 79.4% (95% CI: 75.9-82.6). The overall specificity for P. falciparum detection by the SD 05FK60 was 98.5% (95% CI: 97.7-99.1) and for P. vivax/P. malariae 98.7% (95% CI: 97.9-99.2). The sensitivity for P. falciparum was >91% for parasitaemia levels of >100-1,000 parasites/mul and increased for P. vivax/P. malariae with the parasitaemia level but was overall lower than for P. falciparum.25/408 and 13/420 cases, respectively, of P. falciparum and non-falciparum malaria were missed by the RDT.

CONCLUSION:

In field conditions in Myanmar, the SD 05FK60 malaria RDT performed consistent with other reports. The test detected malaria caused by P. vivax/P. malariae to a lesser extent than P. falciparum infection. Sensitivity improved with increasing parasitaemia level, however even at higher levels some infections were missed. The SD 05FK60 is adequate for use in settings where high quality microscopy is not available.